Spectrum sensing is a key technology in present cognitive radio networks, and would also be crucial in future smart antenna systems, military communication and interference countermeasure. As a kind of radio technology which aims to improve utilization rate of spectrum resources, cognitive radio mainly provides solutions for two challenges. One challenge is that wireless spectrum resources available for allocation are scarce and decreasing continuously. Another challenge is the rather low utilization rate of authorized spectrum. A survey from Federal Communications Commission reveals that, in most cases, the utilization rate is around 10%. This is a huge waste of spectrum resources.
For the reasons above, cognitive radio is developed and promoted. Cognitive radio is a form of wireless communication in which a radio capable of spectrum sensing can temporarily use vacant authorized channels for communication without interference on normal communication of primary users (i.e., authorized users). In this way, utilization rate of spectrum can be improved. Therefore, the prediction of spectrums occupied by primary users is important in cognitive radio networks and remains a pressing issue to be solved.
In prior art, in the case where a primary user has accessed to cognitive radio network, a secondary user typically scans the whole hand. This kind of spectrum access is aimless and its accuracy is very low.